Drink three cups of tea a day and add five years to your life

Drinking tea makes your biological clock tick more slowly. That’s why the molecular age of men over 65 who drink tea is five years younger than you’d expect, write researchers from the Chinese University of Hong Kong in an article soon to be published in the British Journal of Nutrition.

The researchers examined DNA from one thousand older women and a thousand older men. They measured the length of the telomeres in the genetic material. Telomeres are situated at the ends of the chromosomes, the DNA building blocks. [In the illustration the telomeres are the blue/green ‘plugs’ at the end of an X-chromosome.]

The more often cells have divided, and the less often they can divide again, the shorter their telomeres become. Long telomeres are a sign of longevity, although not all researchers are convinced that telomere length really says that much. There is an increasingly large stack of studies in which researchers have not found a relationship between telomere length and life expectancy. On the other hand there is an equally large stack of studies that suggest that longer telomeres are an indication of a longer life.

The researchers asked the test subjects detailed questions about their eating habits, from which they discovered that telomere length in women was closely related to their lifestyle. Only women that consumed high amounts of omega-6 fatty acids in the form of groundnut oil and maize oil had slightly shorter telomeres than women who ate less fat.

Among the men it was a high intake of tea that resulted in longer telomeres. The data in the table below are corrected for all factors that the researchers could think of, so it is unlikely that the tea drinkers had longer telomeres because they had a healthier lifestyle.

The telomeres of the men who drank more than three cups of tea a day [a Chinese cup of tea contains 250 ml] were 0.46 kb longer than the telomeres of the men who only managed 0.3 cups. This difference in telomere length represents "a difference of 5 years of life", according to the researchers.

The most popular type of tea among the men was green tea, with white oolong in second place.

The research was not funded by manufacturers, but by the American and Chinese governments, in the form of the National Institutes of Health and the Research Grants Council of Hong Kong.

EGCG, a flavonoid in green tea, activates life extending enzymes in cells. EGCG works in the same way as resveratrol, a popular supplement among life extensionists. A difference is that it’s difficult to detect unchanged resveratrol in the blood, whereas EGCG shows up quite easily. Maybe therefore the bioavailability of EGCG is higher than that of resveratrol.

Researchers have also found longer telomeres in multivitamin takers, power athletes, people with high levels of vitamin D and people who exercise a lot.